The diagnosis and management of many true vocal cord (TVC) lesions requires biopsy or excision which exposes the patient to the risks of general anesthesia, TVC injury, and potential iatrogenic glottic speech impairment. Unfortunately, many TVC lesions cannot be diagnosed without a biopsy, and this is particularly true with early TVC cancer, where chronic laryngitis is often clinically indistinguishable from malignancy. This application addresses this problem by developing a non-contact imaging device to provide high-resolution cross-sectional images of the TVC using Optical Coherence Tomography (OCT). OCT is an emerging imaging modality that uses low-coherence light to construct high-resolution (10-20 microns), cross-sectional images of tissue to depths of up to 3 mm. The specific aims of this study include: 1) design a high speed OCT instrument coupled to a surgical microscope; 2) obtain in vivo morphometric measurement of human TVC microstructure (e.g.; thickness of epithelium, Reinke's space, etc.); and 3) correlate in vivo OCT images with histology obtained from biopsies. This study will enroll approximately 125 adult patients undergoing laryngeal microendoscopy at UC Irvine Medical Center over two years. In over 60%, a tissue biopsy specimen will be available to allow correlation with conventional histology. Since many of these patients will have a biopsy to diagnose cancer, this study will also provide pilot information on the efficacy of OCT in diagnosing early TVC cancer, where the cardinal feature is invasion of the basement membrane. In addition to structural information on TVC microanatomy, the OCT device will provide functional images of specific tissue properties, including birefringence (collagen organization), using polarization-sensitive OCT, and microscopic blood flow, using Optical Doppler Tomography. We expect our instrument to: 1) image vocal cord microstructure including basement membrane integrity; 2) delineate the superficial and deep extent of both benign and malignant TVC neoplasms; and 3) facilitate real-time image guided microsurgery of the TVC, allowing more accurate tissue biopsies or surgery. Further, OCT imaging will provide a means of documenting the evolution of TVC pathology with 3-D images, thus complementing conventional endoscopy and stroboscopy. Application of OCT to microlaryngeal surgery may reduce iatrogenic phonatory disability by reducing trauma to delicate structures that accompanies conventional techniques. [unreadable] [unreadable]